TORREY PINES – Authorities searched the water and roadsides in north Torrey Pines State Beach for a victim Friday night after a motorist reported hitting a pedestrian.

Accident investigators later theorized that students on the University of California San Diego campus to the south may have tossed an object at the man's car, San Diego police Sgt. Alan Hayward said.

The motorist, described by police as an elderly man, told a state park ranger about 10:15 p.m. that he had hit someone with his car, but he wasn't sure where it happened. The car and windshield were damaged, and officers found that a stop sign had been knocked down in a parking lot.

Police, city lifeguards, park rangers and fire crews searched North Torrey Pines Road near a bridge south of Carmel Valley Road for more than an hour and found no one, authorities said. Most of the searchers broke off their efforts about 11:30 p.m.